Mstislav Leopoldovich Rostropovich (Мстисла́в Леопо́льдович Ростропо́вич) (born March 27, 1927) is a Russian cellist and conductor, considered to be one of the greatest living cellists.

Rostropovich was born in Baku, Azerbaijan (then part of the Soviet Union). From 1943 to 1948, he studied at the Moscow Conservatory, where he became professor of cello in 1956.

Rostropovich left the USSR in 1974 with his wife, the soprano Galina Vishnevskaya whom he had married in 1955. From 1977 until 1994, he was musical director and conductor of the National Symphony Orchestra , Washington, DC

Rostropovich is frequently associated with Prokofiev, whose Cello Concertino he completed after the composer's death. He also gave the first performances of both of the cello concertos of Shostakovich, in 1959 and 1966 respectively. Rostropovich introduced Shostakovich's First Concerto to London in 1960 and began an association with Benjamin Britten, who wrote the Cello Sonata, suites and the Cello Symphony with him in mind.

Because of his public opposition to the USSR’s restriction of cultural freedom, Rostropovich's Soviet citizenship was revoked in 1978 (but restored under new Soviet leadership in 1990).

Rostropovich's instrument is the Duport Stradivarius, a Stradivarius cello built by Antonio Stradivari.